I keep loosing my XM signal, I had an XM radio on before in the same car, never noticed a problem, since I had the D3 installed, it seems to be very frequent

Check your antenna placement, for best reception, it must be outside the vehicle. If its covered or blocked by anything this could be your problem. Unlike the GPS you need a clear line of sight for it to work properly.

Are you using the plate under the antenna?Its true the best place is outside but some people can get away with placing the antenna on the rear deck.If the plate won't work then you'll have to move it outside.

You may have knocked the antenna connector loose from the XM unit during the install...